ad7i (04/12/83)
qst de ad7i holmdel, new jersey, u.s.a. hr propagation forecast bulletin nr 15 from arrl headquarters newington ct april 11, 1983 to all radio amateurs bt on april 8 the solar flux curve rose above the line for the previous solar rotation for the first time since march 23. the solar flux high thus far in april is only 106, but the current appearance of the sun shows more active areas than at any time since the middle of march. this trend should continue for about ten days, but no major rise is expected. geomagnetic activity has been at intermediate levels so far in april, making for propagation quality generally below normal for this time of year. some improvement is likely april 12 through 15 and 18 through 20. mild disturbances will occur intermittently much as they have in recent weeks. the poorest conditions are expected around april 16 and 22. the generally lower levels of solar activity and the change to spring connditions will mean reduced hours of dx on 21 and 28 mhz except for the lower latitudes and on north south paths. the effects of the combined solar and seasonal decline are clearly apparent in the propagation charts shown in qst for april, pages 64 and 65. american sunspot numbers for march 31 through april 6 were between 28 and 57 with a mean of 46.9 ar